Experimental Quantification of the Solubility of SiO2 and H2O in Clinopyroxene Versus Pressure

俯冲洋中脊玄武岩以榴辉岩的形式存在于地幔中，榴辉岩是一种主要由石榴石和单斜辉石组成的岩石。虽然这两种矿物名义上都是无水的，但在许多由火山或构造过程带到地球表面的榴辉岩中发现了少量的水或氢氧化物。水对矿物的物理性质有重大影响。深入了解其发生机制将提高我们对地球地幔中水的运输的理解，并揭示地幔对流和大陆地壳的“再循环”的动力学。该项目将通过一个实验计划来量化水替代的机制，该计划侧重于过量SiO2和OH含量，特别是在4-12 GPa的压力和900- 1200 oC的温度下研究它们与单斜辉石中阳离子空位浓度的相关性。这项工作将扩展和完善以前的榴辉岩的温压解释，并确定水溶解度的上限。这项工作的更广泛的影响包括教育研究生和本科生在先进的分析技术。

Subducted mid-oceanic ridge basalt exists in the Earth's mantle as eclogite, a rock consisting mostly of the minerals garnet and clinopyroxene. Although both of these minerals are nominally anhydrous, a small amount of water or hydroxide has been identified in many eclogites brought to the Earth's surface by volcanic or tectonic processes. Water has major effects on the physical properties of minerals. Insight into the mechanisms of its occurrence will improve our understanding of the transport of water in the Earth's mantle, and cast light on the kinetics of mantle convection and the 'recycling' of the continental crust. This project will quantify the mechanisms for water substitution through an experimental program focused on excess SiO2 and OH contents, especially studying their correlation with cation vacancy concentrations in clinopyroxene at pressures of 4-12 GPa and temperatures of 900-1200oC. This work will extend and refine previous thermobarometric interpretations of eclogites and determine the upper limit of water solubility. The broader impacts of this work include education of graduate and undergraduate students in advanced analytical techniques.